Tip #8(8 of 10)

Trace the trap leak back to the wall. When you have a leak, often it may be on the back side, where it actually connects to the wall, in which case you'll have to disassemble the drain work. Oftentimes you can even tighten it with your hands to see whether the leaking stops. If it doesn't, just use a wrench to tighten it up a little.